A rare handwritten letter that describes how the Queen first fell in love with Prince Philip is set to go up for auction, lending colour to the couple's 68-year marriage. The monarch, who wrote the letter at just 21 when she was still a princess, recounts their first meeting and the early stages of their relationship.

The two-page letter was written to the author Mrs Betty Shew in 1947, just months before the Queen and Prince Philip were married. Mrs Shew was writing a book called Royal Wedding as a souvenir of the marriage, and the then Princess Elizabeth agreed to share details of her relationship with the Prince of Greece and Denmark.

Her Majesty recalled how they first met in 1939 and described how they danced together at nightclubs Ciro's and Quaglino's in London. The letter is written in ink on white paper, which is adorned with the royal crest.

It will go on sale alongside a number of royal artefacts and memorabilia at Chippenham Auction Rooms on Saturday 23 April.

The letter was written in 1947 - the year that the couple married

Principal auctioneer Richard Edmonds said: "This is a wonderfully well-preserved letter written in the Queen's hand. It gives a fascinating glimpse into the life of the then Princess Elizabeth at what was such a significant time in her life. The price of a letter like this is very difficult to predict but it could be in the region of $1,455–$2,180."

Other items set to go up for sale include a life-size waxwork of Queen Victoria which was once displayed in Madame Tussaud's, plus personal items that belonged to Queen Victoria, such as her handkerchiefs and a nightgown.

The royal couple have been married for over 68 years

Collectors will also get the opportunity to purchase a life-size replica of Queen Victoria's son Prince Edward and a replica of Her Majesty's Imperial State Crown, plus replica ceremonial swords, sceptres and maces.